Progressing cavity pump construction



Feb, .9, 1960 ,1. D. BoURKE ET AL '2,924,180

PROGRESSING CAVITY PUMP CONSTRUCTION Filed March 51, 1958 ,f4 Y JJ 24) 2f z lfd ATTORNEYS.

2,924,180 PROGRESSING CAVITY PUMP CONSTRUCTION John David Bourke and Harry Louis Conrad, Springfield, Ohio, assignors to Robbins & Myers, Inc., Springfield, Ohio, a corporation of Ohio Application March 31, 1958, Serial No. 725,119 Claims. (Cl. 10S-117) This invention relates to a progressing cavity type pump construction and relates particularly to improvements use.

ful in connection with high pressure pumps of different types which are dealing with high abrasive or corrosive materials.

In a pump of the progressing cavity type there is an axial thrust against the pump stator in a direction `op-l yUnited States Patent() ticularly adapted because of the fact that the rotor is generally of stainless steel and the stator of rubber, thel casing has been made of high alloys to withstand the corrosive or abrasive action. Actually, however, only certain portions of `the casing come into contact With the abrasive or corrosive material and it is, therefore, an-

other object of the present invention to provide an arrangement whereby only those portions of the-pump which come into contact with the m-aterial being pumped need be made of high alloys.

Another high cost item which enters into the picture in connection with high pressure pumps is the connection of a connecting rod to the pump rotor which will be strong enough to transmit the necessary torque. Rotors for progressing cavity pumps are generally made on a lathe from stainless steel bar stock and in order to provide sufficient stock to -transmit torque at the connecting rod a large size of bar stock must be used, but then the These and other objects of the invention which will be pointed out in more detail hereinafter or which will be apparent to one skilled in the art upon reading these specifications, we accomplish by that certain construction and arrangement of parts of which we shall now disclose an exemplary embodiment.

Reference is made to the drawings forming a part here of and in which:

Figure l is aplan view of a typical high pressure progressing cavity pump according to the invention.

Figure 2 is a fragmentary cross-sectional view on an enlarged scale taken on the line 2-2 of Figure 1.

Figure 3 is a cross-sectional view taken on the line 3-3 of Figure 1, also on an enlarged scale; and

Figure 4 is a cross-sectional view throughthe' stator and stator housing showing the relationship vof the stator and rotor.

- l:Patented Feb. 9,l 196,0

ICC

Briefly, in the practice of our invention, we provide'on the tubular casing within which the stator is mounted, an annular abutment adjacent each end and we provide attachment rings for each end of the tubular casing, each having a cooperating annular abutment. These attachment rings are bolted respectively to the inlet casingportion and to an outlet fitting. In this way thrusts are transmitted by the tubular stator casing to the outlet fitting and to the pump inlet casing. The inlet casing, which serves also for one end of the connecting rod, is secured to a separate casing portion which carries a bearing for the drive shaft and the other end of the connecting rod. The bearing portion of the casing and the inlet portion of the casing are separated and sealed from each other by a sleeve and packing gland. In this way, the portion of the casing having the bearing for the drive shaft need notI be made of a high alloy material because it does not come into contact with the material being which is exposed to the iiuidbeing pumped comprises a stainless steel sleeve pinned both to the rotor and to the connecting rod, as will be described in greater .detail hereinafter.

Referring now in more detail to the drawings, 10 indicates the outlet fitting; 11 the attachment flange bolted thereto by bolts 12; 13 is the pump stator casing; 14 are a plurality of mounting brackets therefor; 15 is another attachment fiange bolted by means of bolts 16 to the inlet and connecting rod casing 17. 18 is the bearing and connecting rod casing which is bolted to the casing 17 by the bolts 19. The drive shaft is indicated at 20.

As best seen in Figure 4, the pump rotor 21 which is generally of stainless steel operates within the stator 22 which is generally of rubber. The principles of the progressing cavity pump are well known and will not be described further herein. The stator 22 is bonded to the stator housing 13. At each end the housing 13fhas a groove and a sealing ring 23 seated therein. Inwardly of the sealing ring 23 at each end of the housing 13, there is provided the annular groove or notch 24. The casing 13 is mounted 'by means of the mounting brackets 14 which do not form a part of the present invention and need not be described further.

At the discharge end of the pump, as best seen in .Figure 3, there is provided the attachment ring ll'which may be bolted by means of the bolts y11a to the casing element 13. The attachment ring 11 has the bolting flange 11b by means of which it is bolted to the bolting flange 10b of the outlet fitting 10 by means of 'the bolts 12. It will be observed that the attachment ring 11 is provided with an annular flange or abutment 11c which engages the annular groove 24 in the casing element 13.

As seen in Figure 2, the attachment ring 15 is provided with the bolting flange 15a and is bolted to the member 17 by the bolts 16. It will also be seen that the member 15 has the annular ange or abutment 15b which engages in the annular groove 24 of the casing 13. Thus, it will he seen that the cooperation between the flangefllc'and v the annular abutment provided bya wall of Vthe groove 24', and between the flange 15b and the annular abutment provided by a wall of the groovey 24 at the other end of Aeiltends-'through the opening 176 and is sealed thereagainst i-'freedom lwith respect to the -pin `31. The end ofthe connecting-'rod T30 istpart-spherical in formandgts within frecessfformed'at the endo'f the shaft`20. The -pin 31 :passesI-throug'h'the hole 32and through holes in 'the shaft 420 andtishe'ld in place by `means Vof screws 33 passing through I'collar 34. The `end of the rotor has vthe cylinfdricallportionla which tits rathertightly into a stainless `steel sleeve 135. A pin 36 passes through the-sleeve 35 and ahole lin -the portion 21a. To the 'right of the pin 35-ani0-rir1g-37 or ,other suitable seal is provided between the rotor 4and the sleeve 35.

The end of the connecting lrod 30 is part-spherical in formasclearlyzseeniiniFigure 2 and also has afared hole 381`through which the pin 39 passes. The Apin 39 also A.passes :through aligned .holes inthe sleeve L35. t By virtue foftthis construction, the connecting lrod 30 may have rocking movement universally to a limiteddegree with respect torthe rotor 21. A suitable mbber seal 40is pro- `.vided to sealwbetween the connecting rod 30 and the sleeve 35.50 thatthe inner `end lof the connecting rod V30, :the rpin 39Iand the ared `hole 38 are protected from and sealed from Vthe iluid fbeing pumped.

The pins 36 and 39 are held in place by `a retaining sleeve 41 vwhich is pressed `rather tightly over the lsleev 35 andagainst abutment -421on ,the sleeve 35.

IBy this construction, the portion 21a of the rotor need not be lof sufficient size toreceive the connecting rod head and transmit the necessary torque because the sleeve and pin construction gives it the necessary strength Vand ,cross-section. In pthis way a large amount of rotor material is saved. Y,It will also be clear Ythat the iiuid being ,pumped contacts only the interior Vof the ycasing .element 417, the connecting rod, the sleeve 28, ,the sleeves 35 and 41, the rotor, the stator, andthe outlet fitting 10. The various brackets 1d and the casing Aelement 18 may 4simply tbe tmade of rcast iron or other inexpensive lma terial.

It will be understood that various modifications may be made without departing `from the spirit of .the invention `and we therefore do not ,intend -to limit ourselves otherwise than as called 4for in `the claims whichtfollow.

Having now `-fully described our invention, what.;we claim as new and desire to secureby Letters Patent is:

.1. `In a helical'gear pump wherein Aan internally helicall-y threaded resilient stator v-pumpingly coacts with an extemally helically `threaded rigid rotor, .a rigid tubular ,casing embracing s aid stator, said `tubular -casing having anannular abutment adjacent each end thereof, `an outlet `iittingand an inlet and connecting rod casing `element fori-said "pump, an attachment `ring ,secured-to said Vtubular casing at each end thereof, each said 'ring having "an annnlar ,abutment cooperating with, .the respective annular ,ahutrnents on .said tubular casing, `one `of said attachment rings being bolted Ytto said outlet itting and the other attachment ring -being bolted to said inlet and connecting :rod .casingelemenb a bearing and connecting `rod casing ,element bolted to said inlet 'and lconnecting `rod `casing element and carrying a drive shaft for Vsaid pump,` a

packing gland sleeve secured to said drive shaft and ex- `tending into said inlet and connecting rod casing, a packling gland surrounding 'said'packing gland sleeve, a connecting ,rod connected at one 'end to said drives'haft and at its other end to said rotor and passing freely through 'said connecting rod and the adjacent `endl of said metallic sleevefsaid outlet `fitting, rotor, `connecting rod, sleeves,

' and inlet and connecting rodfcasing `element being of a material which isnot deleteriously affected bythe uid being pumped. f

2. ln a helical gear pump wherein an'internally helically threaded resilient stator pumpinglyrcoacts with an externally helically threaded rigid rotor, a rigid tubular cas Y ing embracing said stator, said tubular casing having an vannular abutmentadjacent eachend thereof, `an outlet iittingandan inlet `and-connecting rod casing element for `said pump, anattachment ring Vsecured tosaid tubular casing Aat'each end-thereof, eachsaid ring having an annular abutment cooperating with the respectiveannular abutments on said tubular casing, one of'said attachment rings being bolted lto Asaid outlet -fitting andthe other `a`t rod "casing element.

3. In a helical gear pump wherein an internallyhelicaltaohment ringbeing bolted to said inlet and connecting vly Vthreaded stator pumpingly coacts with an `externally -helicall'y threaded rigidrotor, and the rotor orbits in a cylindrical path, 4and wherein a connecting rod `transmits rotation from a drive shaft running on its own vtrue axis to'said orbiting rotor,fa coupling between saidconnect -ing rodvand rotor `comprising a metallic `sleeve fitting tightly over 'the end of said `rotor and a pin passing through `said sleeve and-rotor, `said connecting rod havt ing Ia part-spherical end tting freely within said sleeve and a pin `passing throughsaid-sleeve andconnecting rod, the pin holein said-connecting rodbeing ared to permit rocking movement ofsaidtconnecting rod, sealing means "between said connecting rod and the adjacentend of said sleeve, `and a retaining sleeve fitting over said metallic `sleeve toretain said pins in place. 4. In a high pressure helical gear pump `wherein a internally helicallythreaded stator pumpinglycoacts with `an externally helically threaded rigid rotor, and therotor` orbits in `a vcylindrical Apath, Iand wherein a `connecting rod transmitsrotation -fromla -drive shaft running `on its own true axis to said `orbiting rotor, a high torque coupling -betweensaid connccting rod -and rotor, comprising a metallic sleeve fitted tightly over the end of said rotor vand a pin Apassingthrough said'sleeve and rotor, said` `pinbeingof sutiicientfdiameter and length to transmit 'the requisite torque in shearand compression,` and said `sleeve `'being Lof` suflicient `thickness to lwithstand said torque-after drillingbf ahole'for said pin,fsaid connecting lrod` having a `part-spherical end fitting ffreely within fsaid 'sleeve and alpin passingthroughsaid sleeveand connecting rod, the pin hole in said connecting rod `being flared 5to permit rocking movement of said connecting rod, sealing means Ibetween said connecting rod and` the "adjacent .end ofwsaid sleeve, `and a retaining sleeve tted `over said-metallic sleeve to `retain `said pins in place.

5. In a helical gearzpump fwherein'an internally helically threaded stator pumpingly coacts with an ,externally rhelically threaded rigid rotor, .said pump being useful for pumping materials having a deleteriouseffecton ordinary metals, a bearingzand 'connecting rod Vhousing .membenz an inlettand` connectingrod housing member bolted to said bearing and connecting rodxhousing `member' with communicating bores in alignment,` a stator casingmember bolted Aat -one end lto said inletfand connecting rod housing member, an outlet fitting bolted to the other end of said statorfcasing' member, said stator rbelng disposed in saidstatorfcasing memberysaid rotor being in vpumping engagement within said stator and extending into said inlet and connecting rod housing member, a drive shaft having a bearing in said bearing and connecting rod housing member, a sleeve secured to said drive shaft and extending through said aligned bores into said inlet and connecting rod housing member, 'a packing gland sealing said sleeve with respect to said aligned bores, and a connecting rod connected at one end to said drive shaft in said bearing and connecting rod housing member, passing inside said sleeve into said inlet and connecting rod housing member and connected to said rotor, said inlet and con necting rod housing member, sleeves, connecting rod, connection, rotor, and outlet tting being of a metal which is not deleteriously affected by the uid being pumped.

References Cited in the file of this patent UNITED STATES PATENTS 2,512,765 Byram June 27, 1950 2,527,673 Byram Oct. 31, 1950 2,640,421 Lindberg June 2, 1953 2,733,854 .Chang Feb. 7, 1956 2,739,650 Hill Mar. 27, 1956 2,765,114 Chang Oct. 2, 1956 2,796,029 Bourke June 18, 1957 

